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Re: [perl #129848] heap-buffer-overflow Perl_sv_setpvn (sv.c:4910)

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Dave Mitchell
February 1, 2017 11:16
Re: [perl #129848] heap-buffer-overflow Perl_sv_setpvn (sv.c:4910)
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On Sun, Jan 29, 2017 at 08:15:22PM -0800, Karl Williamson via RT wrote:
> On Fri, 14 Oct 2016 13:42:55 -0700, wrote:
> > I have a new test case that triggers this bug, plus some valgrind output
> > and I have to say, I've never seen `Syscall param write(buf) points to
> > uninitialised byte(s)` before:
> >
> There have been significant changes since this ticket was filed.  I just tried this case in blead with valgrind and got no problems.  This is the output
> Useless use of anonymous hash ({}) in void context at -e line 1.
> Bareword found where operator expected at -e line 1, near "0ÿ"
>         (Missing operator before ÿ?)
> Constant(0): $^H{integer} is not defined at -e line 1, at end of line
> syntax error at -e line 1, near "0ÿ

with the original test03 script, I can bisect it not panicing under
valgrind to

    commit 98d5e3efa825adce1bfa065a5deed791c30162ac
    Author: David Mitchell <>
    Date:   Sat Dec 10 15:06:30 2016 +0000

    misaligned buffer with heredoc and /(?{...})/
    RT #129199

but I can't bisect the test0009 script.

Modern art:
    "That's easy, I could have done that!"
    "Ah, but you didn't!"

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